/* BN_mod_lshift1 variant that may be used if a is non-negative
* and less than m */
int BN_mod_lshift1_quick(BIGNUM *r, const BIGNUM *a, const BIGNUM *m)
{
if (!BN_lshift1(r, a)) return 0;
if (BN_cmp(r, m) >= 0)
return BN_sub(r, r, m);
return 1;
}
int BN_div(BIGNUM *dv, BIGNUM *rem, const BIGNUM *m, const BIGNUM *d,
BN_CTX *ctx)
{
int i,nm,nd;
int ret = 0;
BIGNUM *D;
bn_check_top(m);
bn_check_top(d);
if (BN_is_zero(d))
{
BNerr(BN_F_BN_DIV,BN_R_DIV_BY_ZERO);
return(0);
}
if (BN_ucmp(m,d) < 0)
{
if (rem != NULL)
{ if (BN_copy(rem,m) == NULL) return(0); }
if (dv != NULL) BN_zero(dv);
return(1);
}
BN_CTX_start(ctx);
D = BN_CTX_get(ctx);
if (dv == NULL) dv = BN_CTX_get(ctx);
if (rem == NULL) rem = BN_CTX_get(ctx);
if (D == NULL || dv == NULL || rem == NULL)
goto end;
nd=BN_num_bits(d);
nm=BN_num_bits(m);
if (BN_copy(D,d) == NULL) goto end;
if (BN_copy(rem,m) == NULL) goto end;
/* The next 2 are needed so we can do a dv->d[0]|=1 later
* since BN_lshift1 will only work once there is a value :-) */
BN_zero(dv);
if(bn_wexpand(dv,1) == NULL) goto end;
dv->top=1;
if (!BN_lshift(D,D,nm-nd)) goto end;
for (i=nm-nd; i>=0; i--)
{
if (!BN_lshift1(dv,dv)) goto end;
if (BN_ucmp(rem,D) >= 0)
{
dv->d[0]|=1;
if (!BN_usub(rem,rem,D)) goto end;
}
/* CAN IMPROVE (and have now :=) */
if (!BN_rshift1(D,D)) goto end;
}
rem->neg=BN_is_zero(rem)?0:m->neg;
dv->neg=m->neg^d->neg;
ret = 1;
end:
BN_CTX_end(ctx);
return(ret);
}
int BN_mod_lshift1(BIGNUM *r, const BIGNUM *a, const BIGNUM *m, BN_CTX *ctx)
{
if (!BN_lshift1(r, a))
return 0;
bn_check_top(r);
return BN_nnmod(r, r, m, ctx);
}
/* The secret integers s0 and s1 must be in the range 0 < s < n for
some n, and must be relatively prime to that n. We know a priori
that n is of the form 2**k * p for some small integer k and prime
p. Therefore, it suffices to choose a random integer in the range
[0, n/2), multiply by two and add one (enforcing oddness), and then
reject values which are divisible by p. */
static BIGNUM *
random_s(const BIGNUM *n, const BIGNUM *p, BN_CTX *c)
{
BIGNUM h, m, *r;
BN_init(&h);
BN_init(&m);
FAILZ(r = BN_new());
FAILZ(BN_copy(&h, n));
FAILZ(BN_rshift1(&h, &h));
do {
FAILZ(BN_rand_range(r, &h));
FAILZ(BN_lshift1(r, r));
FAILZ(BN_add(r, r, BN_value_one()));
FAILZ(BN_nnmod(&m, r, p, c));
} while (BN_is_zero(&m));
BN_clear(&h);
BN_clear(&m);
return r;
fail:
BN_clear(&h);
BN_clear(&m);
if (r) BN_clear_free(r);
return 0;
}
static RSA *
fermat_question_ask(const RSA *rsa)
{
BIGNUM
*a = BN_new(),
*b = BN_new(),
*a2 = BN_new(),
*b2 = BN_new();
BIGNUM *n = rsa->n;
BIGNUM
*tmp = BN_new(),
*rem = BN_new(),
*dssdelta = BN_new();
BN_CTX *ctx = BN_CTX_new();
RSA *ret = NULL;
BN_sqrtmod(tmp, rem, n, ctx);
/* Δ = |p - q| = |a + b - a + b| = |2b| > √N 2⁻¹⁰⁰ */
/* BN_rshift(dssdelta, tmp, 101); */
BN_one(dssdelta);
BN_lshift(dssdelta, dssdelta, BN_num_bits(n) / 4 + 10);
BN_copy(a, tmp);
BN_sqr(a2, a, ctx);
do {
/* a² += 2a + 1 */
BN_lshift1(tmp, a);
BN_uiadd1(tmp);
BN_add(a2, a2, tmp);
/* a += 1 */
BN_uiadd1(a);
/* b² = a² - N */
BN_usub(b2, a2, n);
/* b */
BN_sqrtmod(b, rem, b2, ctx);
} while (!BN_is_zero(rem) && BN_cmp(b, dssdelta) < 1);
if (BN_is_zero(rem)) {
BN_uadd(a, a, b);
ret = qa_RSA_recover(rsa, a, ctx);
}
BN_CTX_free(ctx);
BN_free(a);
BN_free(b);
BN_free(a2);
BN_free(b2);
BN_free(dssdelta);
BN_free(tmp);
BN_free(rem);
return ret;
}
static int probable_prime_dh_safe(BIGNUM *p, int bits, const BIGNUM *padd,
const BIGNUM *rem, BN_CTX *ctx)
{
int i,ret=0;
BIGNUM *t1,*qadd,*q;
bits--;
BN_CTX_start(ctx);
t1 = BN_CTX_get(ctx);
q = BN_CTX_get(ctx);
qadd = BN_CTX_get(ctx);
if (qadd == NULL) goto err;
if (!BN_rshift1(qadd,padd)) goto err;
if (!BN_rand(q,bits,0,1)) goto err;
/* we need ((rnd-rem) % add) == 0 */
if (!BN_mod(t1,q,qadd,ctx)) goto err;
if (!BN_sub(q,q,t1)) goto err;
if (rem == NULL)
{ if (!BN_add_word(q,1)) goto err; }
else
{
if (!BN_rshift1(t1,rem)) goto err;
if (!BN_add(q,q,t1)) goto err;
}
/* we now have a random number 'rand' to test. */
if (!BN_lshift1(p,q)) goto err;
if (!BN_add_word(p,1)) goto err;
loop:
for (i=1; i<NUMPRIMES; i++)
{
/* check that p and q are prime */
/* check that for p and q
* gcd(p-1,primes) == 1 (except for 2) */
if ((BN_mod_word(p,(BN_ULONG)primes[i]) == 0) ||
(BN_mod_word(q,(BN_ULONG)primes[i]) == 0))
{
if (!BN_add(p,p,padd)) goto err;
if (!BN_add(q,q,qadd)) goto err;
goto loop;
}
}
ret=1;
err:
BN_CTX_end(ctx);
bn_check_top(p);
return(ret);
}
// http://stackoverflow.com/questions/356090/how-to-compute-the-nth-root-of-a-very-big-integer
static BIGNUM *nearest_cuberoot(BIGNUM *in)
{
BN_CTX *ctx = BN_CTX_new();
BN_CTX_start(ctx);
BIGNUM *three = BN_CTX_get(ctx);
BIGNUM *high = BN_CTX_get(ctx);
BIGNUM *mid = BN_CTX_get(ctx);
BIGNUM *low = BN_CTX_get(ctx);
BIGNUM *tmp = BN_CTX_get(ctx);
BN_set_word(three, 3); // Create the constant 3
BN_set_word(high, 1); // high = 1
do
{
BN_lshift1(high, high); // high = high << 1 (high * 2)
BN_exp(tmp, high, three, ctx); // tmp = high^3
} while (BN_ucmp(tmp, in) <= -1); // while (tmp < in)
BN_rshift1(low, high); // low = high >> 1 (high / 2)
while (BN_ucmp(low, high) <= -1) // while (low < high)
{
BN_add(tmp, low, high); // tmp = low + high
BN_rshift1(mid, tmp); // mid = tmp >> 1 (tmp / 2)
BN_exp(tmp, mid, three, ctx); // tmp = mid^3
if (BN_ucmp(low, mid) <= -1 && BN_ucmp(tmp, in) <= -1) // if (low < mid && tmp < in)
BN_copy(low, mid); // low = mid
else if (BN_ucmp(high, mid) >= 1 && BN_ucmp(tmp, in) >= 1) // else if (high > mid && tmp > in)
BN_copy(high, mid); // high = mid
else
{
// subtract 1 from mid because 1 will be added after the loop
BN_sub_word(mid, 1); // mid -= 1
break;
}
}
BN_add_word(mid, 1); // mid += 1
BIGNUM *result = BN_dup(mid);
BN_CTX_end(ctx);
BN_CTX_free(ctx);
return result;
}
/* BN_mod_lshift variant that may be used if a is non-negative
* and less than m */
int BN_mod_lshift_quick(BIGNUM *r, const BIGNUM *a, int n, const BIGNUM *m)
{
if (r != a)
{
if (BN_copy(r, a) == NULL) return 0;
}
while (n > 0)
{
int max_shift;
/* 0 < r < m */
max_shift = BN_num_bits(m) - BN_num_bits(r);
/* max_shift >= 0 */
if (max_shift < 0)
{
BNerr(BN_F_BN_MOD_LSHIFT_QUICK, BN_R_INPUT_NOT_REDUCED);
return 0;
}
if (max_shift > n)
max_shift = n;
if (max_shift)
{
if (!BN_lshift(r, r, max_shift)) return 0;
n -= max_shift;
}
else
{
if (!BN_lshift1(r, r)) return 0;
--n;
}
/* BN_num_bits(r) <= BN_num_bits(m) */
if (BN_cmp(r, m) >= 0)
{
if (!BN_sub(r, r, m)) return 0;
}
}
bn_check_top(r);
return 1;
}
int test_lshift1(BIO *bp)
{
BIGNUM *a,*b,*c;
int i;
a=BN_new();
b=BN_new();
c=BN_new();
BN_bntest_rand(a,200,0,0); /**/
a->neg=rand_neg();
for (i=0; i<num0; i++)
{
BN_lshift1(b,a);
if (bp != NULL)
{
if (!results)
{
BN_print(bp,a);
BIO_puts(bp," * 2");
BIO_puts(bp," - ");
}
BN_print(bp,b);
BIO_puts(bp,"\n");
}
BN_add(c,a,a);
BN_sub(a,b,c);
if(!BN_is_zero(a))
{
fprintf(stderr,"Left shift one test failed!\n");
return 0;
}
BN_copy(a,b);
}
BN_free(a);
BN_free(b);
BN_free(c);
return(1);
}
static int test_check_public_key(void)
{
int ret = 0;
BIGNUM *n = NULL, *e = NULL;
RSA *key = NULL;
ret = TEST_ptr(key = RSA_new())
/* check NULL pointers fail */
&& TEST_false(rsa_sp800_56b_check_public(key))
/* load public key */
&& TEST_ptr(e = bn_load_new(cav_e, sizeof(cav_e)))
&& TEST_ptr(n = bn_load_new(cav_n, sizeof(cav_n)))
&& TEST_true(RSA_set0_key(key, n, e, NULL));
if (!ret) {
BN_free(e);
BN_free(n);
goto end;
}
/* check public key is valid */
ret = TEST_true(rsa_sp800_56b_check_public(key))
/* check fail if n is even */
&& TEST_true(BN_add_word(n, 1))
&& TEST_false(rsa_sp800_56b_check_public(key))
&& TEST_true(BN_sub_word(n, 1))
/* check fail if n is wrong number of bits */
&& TEST_true(BN_lshift1(n, n))
&& TEST_false(rsa_sp800_56b_check_public(key))
&& TEST_true(BN_rshift1(n, n))
/* test odd exponent fails */
&& TEST_true(BN_add_word(e, 1))
&& TEST_false(rsa_sp800_56b_check_public(key))
&& TEST_true(BN_sub_word(e, 1))
/* modulus fails composite check */
&& TEST_true(BN_add_word(n, 2))
&& TEST_false(rsa_sp800_56b_check_public(key));
end:
RSA_free(key);
return ret;
}
int
dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits, const EVP_MD *evpmd,
const unsigned char *seed_in, size_t seed_len, unsigned char *seed_out,
int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
{
int ok = 0;
unsigned char seed[SHA256_DIGEST_LENGTH];
unsigned char md[SHA256_DIGEST_LENGTH];
unsigned char buf[SHA256_DIGEST_LENGTH], buf2[SHA256_DIGEST_LENGTH];
BIGNUM *r0, *W, *X, *c, *test;
BIGNUM *g = NULL, *q = NULL, *p = NULL;
BN_MONT_CTX *mont = NULL;
int i, k, n = 0, m = 0, qsize = qbits >> 3;
int counter = 0;
int r = 0;
BN_CTX *ctx = NULL;
unsigned int h = 2;
if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH &&
qsize != SHA256_DIGEST_LENGTH)
/* invalid q size */
return 0;
if (evpmd == NULL)
/* use SHA1 as default */
evpmd = EVP_sha1();
if (bits < 512)
bits = 512;
bits = (bits + 63) / 64 * 64;
/*
* NB: seed_len == 0 is special case: copy generated seed to
* seed_in if it is not NULL.
*/
if (seed_len && seed_len < (size_t)qsize)
seed_in = NULL; /* seed buffer too small -- ignore */
/*
* App. 2.2 of FIPS PUB 186 allows larger SEED,
* but our internal buffers are restricted to 160 bits
*/
if (seed_len > (size_t)qsize)
seed_len = qsize;
if (seed_in != NULL)
memcpy(seed, seed_in, seed_len);
if ((ctx=BN_CTX_new()) == NULL)
goto err;
if ((mont=BN_MONT_CTX_new()) == NULL)
goto err;
BN_CTX_start(ctx);
r0 = BN_CTX_get(ctx);
g = BN_CTX_get(ctx);
W = BN_CTX_get(ctx);
q = BN_CTX_get(ctx);
X = BN_CTX_get(ctx);
c = BN_CTX_get(ctx);
p = BN_CTX_get(ctx);
test = BN_CTX_get(ctx);
if (!BN_lshift(test, BN_value_one(), bits - 1))
goto err;
for (;;) {
for (;;) { /* find q */
int seed_is_random;
/* step 1 */
if (!BN_GENCB_call(cb, 0, m++))
goto err;
if (!seed_len) {
RAND_pseudo_bytes(seed, qsize);
seed_is_random = 1;
} else {
seed_is_random = 0;
/* use random seed if 'seed_in' turns out
to be bad */
seed_len = 0;
}
memcpy(buf, seed, qsize);
memcpy(buf2, seed, qsize);
/* precompute "SEED + 1" for step 7: */
for (i = qsize - 1; i >= 0; i--) {
buf[i]++;
if (buf[i] != 0)
break;
}
/* step 2 */
if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL))
goto err;
if (!EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL))
goto err;
for (i = 0; i < qsize; i++)
md[i] ^= buf2[i];
/* step 3 */
md[0] |= 0x80;
md[qsize - 1] |= 0x01;
if (!BN_bin2bn(md, qsize, q))
goto err;
/* step 4 */
r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
seed_is_random, cb);
if (r > 0)
break;
if (r != 0)
goto err;
/* do a callback call */
/* step 5 */
}
if (!BN_GENCB_call(cb, 2, 0))
goto err;
if (!BN_GENCB_call(cb, 3, 0))
goto err;
/* step 6 */
counter = 0;
/* "offset = 2" */
n = (bits - 1) / 160;
for (;;) {
if (counter != 0 && !BN_GENCB_call(cb, 0, counter))
goto err;
/* step 7 */
BN_zero(W);
/* now 'buf' contains "SEED + offset - 1" */
for (k = 0; k <= n; k++) {
/* obtain "SEED + offset + k" by incrementing: */
for (i = qsize - 1; i >= 0; i--) {
buf[i]++;
if (buf[i] != 0)
break;
}
if (!EVP_Digest(buf, qsize, md ,NULL, evpmd,
NULL))
goto err;
/* step 8 */
if (!BN_bin2bn(md, qsize, r0))
goto err;
if (!BN_lshift(r0, r0, (qsize << 3) * k))
goto err;
if (!BN_add(W, W, r0))
goto err;
}
/* more of step 8 */
if (!BN_mask_bits(W, bits - 1))
goto err;
if (!BN_copy(X, W))
goto err;
if (!BN_add(X, X, test))
goto err;
/* step 9 */
if (!BN_lshift1(r0, q))
goto err;
if (!BN_mod(c, X, r0, ctx))
goto err;
if (!BN_sub(r0, c, BN_value_one()))
goto err;
if (!BN_sub(p, X, r0))
goto err;
/* step 10 */
if (BN_cmp(p, test) >= 0) {
/* step 11 */
r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
ctx, 1, cb);
if (r > 0)
goto end; /* found it */
if (r != 0)
goto err;
}
/* step 13 */
counter++;
/* "offset = offset + n + 1" */
/* step 14 */
if (counter >= 4096)
break;
}
}
end:
if (!BN_GENCB_call(cb, 2, 1))
goto err;
/* We now need to generate g */
/* Set r0=(p-1)/q */
if (!BN_sub(test, p, BN_value_one()))
goto err;
if (!BN_div(r0, NULL, test, q, ctx))
goto err;
if (!BN_set_word(test, h))
goto err;
if (!BN_MONT_CTX_set(mont, p, ctx))
goto err;
for (;;) {
/* g=test^r0%p */
if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
goto err;
if (!BN_is_one(g))
break;
if (!BN_add(test, test, BN_value_one()))
goto err;
h++;
}
if (!BN_GENCB_call(cb, 3, 1))
goto err;
ok = 1;
err:
if (ok) {
if (ret->p)
BN_free(ret->p);
if (ret->q)
BN_free(ret->q);
if (ret->g)
BN_free(ret->g);
ret->p = BN_dup(p);
ret->q = BN_dup(q);
ret->g = BN_dup(g);
if (ret->p == NULL || ret->q == NULL || ret->g == NULL) {
ok = 0;
goto err;
}
if (counter_ret != NULL)
*counter_ret = counter;
if (h_ret != NULL)
*h_ret = h;
if (seed_out)
memcpy(seed_out, seed, qsize);
}
if (ctx) {
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
if (mont != NULL)
BN_MONT_CTX_free(mont);
return ok;
}
BIGNUM *BN_mod_inverse(BIGNUM *in,
const BIGNUM *a, const BIGNUM *n, BN_CTX *ctx)
{
BIGNUM *A,*B,*X,*Y,*M,*D,*T,*R=NULL;
BIGNUM *ret=NULL;
int sign;
if ((BN_get_flags(a, BN_FLG_CONSTTIME) != 0) || (BN_get_flags(n, BN_FLG_CONSTTIME) != 0))
{
return BN_mod_inverse_no_branch(in, a, n, ctx);
}
bn_check_top(a);
bn_check_top(n);
BN_CTX_start(ctx);
A = BN_CTX_get(ctx);
B = BN_CTX_get(ctx);
X = BN_CTX_get(ctx);
D = BN_CTX_get(ctx);
M = BN_CTX_get(ctx);
Y = BN_CTX_get(ctx);
T = BN_CTX_get(ctx);
if (T == NULL) goto err;
if (in == NULL)
R=BN_new();
else
R=in;
if (R == NULL) goto err;
BN_one(X);
BN_zero(Y);
if (BN_copy(B,a) == NULL) goto err;
if (BN_copy(A,n) == NULL) goto err;
A->neg = 0;
if (B->neg || (BN_ucmp(B, A) >= 0))
{
if (!BN_nnmod(B, B, A, ctx)) goto err;
}
sign = -1;
/* From B = a mod |n|, A = |n| it follows that
*
* 0 <= B < A,
* -sign*X*a == B (mod |n|),
* sign*Y*a == A (mod |n|).
*/
if (BN_is_odd(n) && (BN_num_bits(n) <= (BN_BITS <= 32 ? 450 : 2048)))
{
/* Binary inversion algorithm; requires odd modulus.
* This is faster than the general algorithm if the modulus
* is sufficiently small (about 400 .. 500 bits on 32-bit
* sytems, but much more on 64-bit systems) */
int shift;
while (!BN_is_zero(B))
{
/*
* 0 < B < |n|,
* 0 < A <= |n|,
* (1) -sign*X*a == B (mod |n|),
* (2) sign*Y*a == A (mod |n|)
*/
/* Now divide B by the maximum possible power of two in the integers,
* and divide X by the same value mod |n|.
* When we're done, (1) still holds. */
shift = 0;
while (!BN_is_bit_set(B, shift)) /* note that 0 < B */
{
shift++;
if (BN_is_odd(X))
{
if (!BN_uadd(X, X, n)) goto err;
}
/* now X is even, so we can easily divide it by two */
if (!BN_rshift1(X, X)) goto err;
}
if (shift > 0)
{
if (!BN_rshift(B, B, shift)) goto err;
}
/* Same for A and Y. Afterwards, (2) still holds. */
shift = 0;
while (!BN_is_bit_set(A, shift)) /* note that 0 < A */
{
shift++;
if (BN_is_odd(Y))
{
if (!BN_uadd(Y, Y, n)) goto err;
}
/* now Y is even */
if (!BN_rshift1(Y, Y)) goto err;
}
if (shift > 0)
{
if (!BN_rshift(A, A, shift)) goto err;
}
/* We still have (1) and (2).
* Both A and B are odd.
* The following computations ensure that
*
* 0 <= B < |n|,
* 0 < A < |n|,
* (1) -sign*X*a == B (mod |n|),
* (2) sign*Y*a == A (mod |n|),
*
* and that either A or B is even in the next iteration.
*/
if (BN_ucmp(B, A) >= 0)
{
/* -sign*(X + Y)*a == B - A (mod |n|) */
if (!BN_uadd(X, X, Y)) goto err;
/* NB: we could use BN_mod_add_quick(X, X, Y, n), but that
* actually makes the algorithm slower */
if (!BN_usub(B, B, A)) goto err;
}
else
{
/* sign*(X + Y)*a == A - B (mod |n|) */
if (!BN_uadd(Y, Y, X)) goto err;
/* as above, BN_mod_add_quick(Y, Y, X, n) would slow things down */
if (!BN_usub(A, A, B)) goto err;
}
}
}
else
{
/* general inversion algorithm */
while (!BN_is_zero(B))
{
BIGNUM *tmp;
/*
* 0 < B < A,
* (*) -sign*X*a == B (mod |n|),
* sign*Y*a == A (mod |n|)
*/
/* (D, M) := (A/B, A%B) ... */
if (BN_num_bits(A) == BN_num_bits(B))
{
if (!BN_one(D)) goto err;
if (!BN_sub(M,A,B)) goto err;
}
else if (BN_num_bits(A) == BN_num_bits(B) + 1)
{
/* A/B is 1, 2, or 3 */
if (!BN_lshift1(T,B)) goto err;
if (BN_ucmp(A,T) < 0)
{
/* A < 2*B, so D=1 */
if (!BN_one(D)) goto err;
if (!BN_sub(M,A,B)) goto err;
}
else
{
/* A >= 2*B, so D=2 or D=3 */
if (!BN_sub(M,A,T)) goto err;
if (!BN_add(D,T,B)) goto err; /* use D (:= 3*B) as temp */
if (BN_ucmp(A,D) < 0)
{
/* A < 3*B, so D=2 */
if (!BN_set_word(D,2)) goto err;
/* M (= A - 2*B) already has the correct value */
}
else
{
/* only D=3 remains */
if (!BN_set_word(D,3)) goto err;
/* currently M = A - 2*B, but we need M = A - 3*B */
if (!BN_sub(M,M,B)) goto err;
}
}
}
else
{
if (!BN_div(D,M,A,B,ctx)) goto err;
}
/* Now
* A = D*B + M;
* thus we have
* (**) sign*Y*a == D*B + M (mod |n|).
*/
tmp=A; /* keep the BIGNUM object, the value does not matter */
/* (A, B) := (B, A mod B) ... */
A=B;
B=M;
/* ... so we have 0 <= B < A again */
/* Since the former M is now B and the former B is now A,
* (**) translates into
* sign*Y*a == D*A + B (mod |n|),
* i.e.
* sign*Y*a - D*A == B (mod |n|).
* Similarly, (*) translates into
* -sign*X*a == A (mod |n|).
*
* Thus,
* sign*Y*a + D*sign*X*a == B (mod |n|),
* i.e.
* sign*(Y + D*X)*a == B (mod |n|).
*
* So if we set (X, Y, sign) := (Y + D*X, X, -sign), we arrive back at
* -sign*X*a == B (mod |n|),
* sign*Y*a == A (mod |n|).
* Note that X and Y stay non-negative all the time.
*/
/* most of the time D is very small, so we can optimize tmp := D*X+Y */
if (BN_is_one(D))
{
if (!BN_add(tmp,X,Y)) goto err;
}
else
{
if (BN_is_word(D,2))
{
if (!BN_lshift1(tmp,X)) goto err;
}
else if (BN_is_word(D,4))
{
if (!BN_lshift(tmp,X,2)) goto err;
}
else if (D->top == 1)
{
if (!BN_copy(tmp,X)) goto err;
if (!BN_mul_word(tmp,D->d[0])) goto err;
}
else
{
if (!BN_mul(tmp,D,X,ctx)) goto err;
}
if (!BN_add(tmp,tmp,Y)) goto err;
}
M=Y; /* keep the BIGNUM object, the value does not matter */
Y=X;
X=tmp;
sign = -sign;
}
}
/*
* The while loop (Euclid's algorithm) ends when
* A == gcd(a,n);
* we have
* sign*Y*a == A (mod |n|),
* where Y is non-negative.
*/
if (sign < 0)
{
if (!BN_sub(Y,n,Y)) goto err;
}
/* Now Y*a == A (mod |n|). */
if (BN_is_one(A))
{
/* Y*a == 1 (mod |n|) */
if (!Y->neg && BN_ucmp(Y,n) < 0)
{
if (!BN_copy(R,Y)) goto err;
}
else
{
if (!BN_nnmod(R,Y,n,ctx)) goto err;
}
}
else
{
BNerr(BN_F_BN_MOD_INVERSE,BN_R_NO_INVERSE);
goto err;
}
ret=R;
err:
if ((ret == NULL) && (in == NULL)) BN_free(R);
BN_CTX_end(ctx);
bn_check_top(ret);
return(ret);
}
int xDSA_paramgen(DSA *ret, int bits)
{
int ok=0;
unsigned char seed[SHA_DIGEST_LENGTH];
unsigned char md[SHA_DIGEST_LENGTH];
unsigned char buf[SHA_DIGEST_LENGTH], buf2[SHA_DIGEST_LENGTH];
BIGNUM *r0, *W, *X, *c, *test;
BIGNUM *g=NULL, *q=NULL, *p=NULL;
BN_MONT_CTX *mont=NULL;
int k, n=0, i, b;
int counter=0;
int r=0;
BN_CTX *ctx=NULL;
unsigned int h=2;
if (bits < 512)
bits=512;
bits=(bits+63)/64*64;
if ((ctx=BN_CTX_new()) == NULL)
goto err;
if ((mont=BN_MONT_CTX_new()) == NULL)
goto err;
BN_CTX_start(ctx);
r0 = BN_CTX_get(ctx);
g = BN_CTX_get(ctx);
W = BN_CTX_get(ctx);
q = BN_CTX_get(ctx);
X = BN_CTX_get(ctx);
c = BN_CTX_get(ctx);
p = BN_CTX_get(ctx);
test = BN_CTX_get(ctx);
if (!BN_lshift(test, BN_value_one(), bits-1))
goto err;
for (;;) {
for (;;) /* find q */
{
int seed_is_random;
/* step 1 */
xRAND_bytes(seed, SHA_DIGEST_LENGTH);
seed_is_random = 1;
memcpy(buf, seed, SHA_DIGEST_LENGTH);
memcpy(buf2, seed, SHA_DIGEST_LENGTH);
/* precompute "SEED + 1" for step 7: */
for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--) {
buf[i]++;
if (buf[i] != 0)
break;
}
/* step 2 */
EVP_Digest(seed, SHA_DIGEST_LENGTH, md, NULL, HASH, NULL);
EVP_Digest(buf, SHA_DIGEST_LENGTH, buf2, NULL, HASH, NULL);
for (i=0; i<SHA_DIGEST_LENGTH; i++)
md[i]^=buf2[i];
/* step 3 */
md[0]|=0x80;
md[SHA_DIGEST_LENGTH-1]|=0x01;
if (!BN_bin2bn(md, SHA_DIGEST_LENGTH, q))
goto err;
/* step 4 */
r = xBN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
seed_is_random);
if (r > 0)
break;
if (r != 0)
goto err;
/* do a callback call */
/* step 5 */
}
/* step 6 */
counter=0;
/* "offset = 2" */
n=(bits-1)/160;
b=(bits-1)-n*160;
for (;;) {
/* step 7 */
BN_zero(W);
/* now 'buf' contains "SEED + offset - 1" */
for (k=0; k<=n; k++) {
/* obtain "SEED + offset + k" by incrementing: */
for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--) {
buf[i]++;
if (buf[i] != 0)
break;
}
EVP_Digest(buf, SHA_DIGEST_LENGTH, md, NULL, HASH, NULL);
/* step 8 */
if (!BN_bin2bn(md, SHA_DIGEST_LENGTH, r0))
goto err;
if (!BN_lshift(r0, r0, 160*k))
goto err;
if (!BN_add(W, W, r0))
goto err;
}
/* more of step 8 */
if (!BN_mask_bits(W, bits-1))
goto err;
if (!BN_copy(X, W))
goto err;
if (!BN_add(X, X, test))
goto err;
/* step 9 */
if (!BN_lshift1(r0, q))
goto err;
if (!BN_mod(c,X,r0,ctx))
goto err;
if (!BN_sub(r0, c, BN_value_one()))
goto err;
if (!BN_sub(p, X, r0))
goto err;
/* step 10 */
if (BN_cmp(p, test) >= 0) {
/* step 11 */
r = xBN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1);
if (r > 0)
goto end;
/* found it */
if (r != 0)
goto err;
}
/* step 13 */
counter++;
/* "offset = offset + n + 1" */
/* step 14 */
if (counter >= 4096)
break;
}
}
end:
/* We now need to generate g */
/* Set r0=(p-1)/q */
if (!BN_sub(test, p, BN_value_one()))
goto err;
if (!BN_div(r0, NULL, test, q, ctx))
goto err;
if (!BN_set_word(test, h))
goto err;
if (!BN_MONT_CTX_set(mont, p, ctx))
goto err;
for (;;) {
/* g=test^r0%p */
if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
goto err;
if (!BN_is_one(g))
break;
if (!BN_add(test, test, BN_value_one()))
goto err;
h++;
}
ok=1;
err:
if (ok) {
if (ret->p)
BN_free(ret->p);
if (ret->q)
BN_free(ret->q);
if (ret->g)
BN_free(ret->g);
ret->p=BN_dup(p);
ret->q=BN_dup(q);
ret->g=BN_dup(g);
if (ret->p == NULL || ret->q == NULL || ret->g == NULL) {
ok=0;
goto err;
}
}
if (ctx) {
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
if (mont != NULL)
BN_MONT_CTX_free(mont);
return ok;
}
int dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N,
const EVP_MD *evpmd, const unsigned char *seed_in, size_t seed_len,
unsigned char *seed_out,
int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
{
int ok=-1;
unsigned char *seed = NULL;
unsigned char md[EVP_MAX_MD_SIZE];
int mdsize;
BIGNUM *r0,*W,*X,*c,*test;
BIGNUM *g=NULL,*q=NULL,*p=NULL;
BN_MONT_CTX *mont=NULL;
int i, k, n=0, m=0, qsize = N >> 3;
int counter=0;
int r=0;
BN_CTX *ctx=NULL;
unsigned int h=2;
#ifdef OPENSSL_FIPS
if(FIPS_selftest_failed())
{
FIPSerr(FIPS_F_DSA_BUILTIN_PARAMGEN2,
FIPS_R_FIPS_SELFTEST_FAILED);
goto err;
}
if (!fips_check_dsa_prng(ret, L, N))
goto err;
#endif
if (evpmd == NULL)
{
if (N == 160)
evpmd = EVP_sha1();
else if (N == 224)
evpmd = EVP_sha224();
else
evpmd = EVP_sha256();
}
mdsize = M_EVP_MD_size(evpmd);
if (seed_len == 0)
seed_len = mdsize;
seed = OPENSSL_malloc(seed_len);
if (!seed)
goto err;
if (seed_in)
memcpy(seed, seed_in, seed_len);
if ((ctx=BN_CTX_new()) == NULL)
goto err;
if ((mont=BN_MONT_CTX_new()) == NULL)
goto err;
BN_CTX_start(ctx);
r0 = BN_CTX_get(ctx);
g = BN_CTX_get(ctx);
W = BN_CTX_get(ctx);
q = BN_CTX_get(ctx);
X = BN_CTX_get(ctx);
c = BN_CTX_get(ctx);
p = BN_CTX_get(ctx);
test = BN_CTX_get(ctx);
if (!BN_lshift(test,BN_value_one(),L-1))
goto err;
for (;;)
{
for (;;) /* find q */
{
unsigned char *pmd;
/* step 1 */
if(!BN_GENCB_call(cb, 0, m++))
goto err;
if (!seed_in)
{
if (RAND_pseudo_bytes(seed, seed_len) < 0)
goto err;
}
/* step 2 */
if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
goto err;
/* Take least significant bits of md */
if (mdsize > qsize)
pmd = md + mdsize - qsize;
else
pmd = md;
if (mdsize < qsize)
memset(md + mdsize, 0, qsize - mdsize);
/* step 3 */
pmd[0] |= 0x80;
pmd[qsize-1] |= 0x01;
if (!BN_bin2bn(pmd, qsize, q))
goto err;
/* step 4 */
r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
seed_in ? 1 : 0, cb);
if (r > 0)
break;
if (r != 0)
goto err;
/* Provided seed didn't produce a prime: error */
if (seed_in)
{
ok = 0;
DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_Q_NOT_PRIME);
goto err;
}
/* do a callback call */
/* step 5 */
}
/* Copy seed to seed_out before we mess with it */
if (seed_out)
memcpy(seed_out, seed, seed_len);
if(!BN_GENCB_call(cb, 2, 0)) goto err;
if(!BN_GENCB_call(cb, 3, 0)) goto err;
/* step 6 */
counter=0;
/* "offset = 1" */
n=(L-1)/(mdsize << 3);
for (;;)
{
if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
goto err;
/* step 7 */
BN_zero(W);
/* now 'buf' contains "SEED + offset - 1" */
for (k=0; k<=n; k++)
{
/* obtain "SEED + offset + k" by incrementing: */
for (i = seed_len-1; i >= 0; i--)
{
seed[i]++;
if (seed[i] != 0)
break;
}
if (!EVP_Digest(seed, seed_len, md ,NULL, evpmd,
NULL))
goto err;
/* step 8 */
if (!BN_bin2bn(md, mdsize, r0))
goto err;
if (!BN_lshift(r0,r0,(mdsize << 3)*k)) goto err;
if (!BN_add(W,W,r0)) goto err;
}
/* more of step 8 */
if (!BN_mask_bits(W,L-1)) goto err;
if (!BN_copy(X,W)) goto err;
if (!BN_add(X,X,test)) goto err;
/* step 9 */
if (!BN_lshift1(r0,q)) goto err;
if (!BN_mod(c,X,r0,ctx)) goto err;
if (!BN_sub(r0,c,BN_value_one())) goto err;
if (!BN_sub(p,X,r0)) goto err;
/* step 10 */
if (BN_cmp(p,test) >= 0)
{
/* step 11 */
r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
ctx, 1, cb);
if (r > 0)
goto end; /* found it */
if (r != 0)
goto err;
}
/* step 13 */
counter++;
/* "offset = offset + n + 1" */
/* step 14 */
if (counter >= 4096) break;
}
}
end:
if(!BN_GENCB_call(cb, 2, 1))
goto err;
/* We now need to generate g */
/* Set r0=(p-1)/q */
if (!BN_sub(test,p,BN_value_one())) goto err;
if (!BN_div(r0,NULL,test,q,ctx)) goto err;
if (!BN_set_word(test,h)) goto err;
if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
for (;;)
{
/* g=test^r0%p */
if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
if (!BN_is_one(g)) break;
if (!BN_add(test,test,BN_value_one())) goto err;
h++;
}
if(!BN_GENCB_call(cb, 3, 1))
goto err;
ok=1;
err:
if (ok == 1)
{
if(ret->p) BN_free(ret->p);
if(ret->q) BN_free(ret->q);
if(ret->g) BN_free(ret->g);
ret->p=BN_dup(p);
ret->q=BN_dup(q);
ret->g=BN_dup(g);
if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
{
ok=-1;
goto err;
}
if (counter_ret != NULL) *counter_ret=counter;
if (h_ret != NULL) *h_ret=h;
}
if (seed)
OPENSSL_free(seed);
if(ctx)
{
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
if (mont != NULL) BN_MONT_CTX_free(mont);
return ok;
}
DSA *DSA_generate_parameters(int bits,
unsigned char *seed_in, int seed_len,
int *counter_ret, unsigned long *h_ret,
void (*callback)(int, int, void *),
void *cb_arg)
{
int ok=0;
unsigned char seed[SHA_DIGEST_LENGTH];
unsigned char md[SHA_DIGEST_LENGTH];
unsigned char buf[SHA_DIGEST_LENGTH],buf2[SHA_DIGEST_LENGTH];
BIGNUM *r0,*W,*X,*c,*test;
BIGNUM *g=NULL,*q=NULL,*p=NULL;
BN_MONT_CTX *mont=NULL;
int k,n=0,i,b,m=0;
int counter=0;
int r=0;
BN_CTX *ctx=NULL,*ctx2=NULL,*ctx3=NULL;
unsigned int h=2;
DSA *ret=NULL;
if (bits < 512) bits=512;
bits=(bits+63)/64*64;
if (seed_len < 20)
seed_in = NULL; /* seed buffer too small -- ignore */
if (seed_len > 20)
seed_len = 20; /* App. 2.2 of FIPS PUB 186 allows larger SEED,
* but our internal buffers are restricted to 160 bits*/
if ((seed_in != NULL) && (seed_len == 20))
memcpy(seed,seed_in,seed_len);
if ((ctx=BN_CTX_new()) == NULL) goto err;
if ((ctx2=BN_CTX_new()) == NULL) goto err;
if ((ctx3=BN_CTX_new()) == NULL) goto err;
if ((ret=DSA_new()) == NULL) goto err;
if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
BN_CTX_start(ctx2);
r0 = BN_CTX_get(ctx2);
g = BN_CTX_get(ctx2);
W = BN_CTX_get(ctx2);
q = BN_CTX_get(ctx2);
X = BN_CTX_get(ctx2);
c = BN_CTX_get(ctx2);
p = BN_CTX_get(ctx2);
test = BN_CTX_get(ctx2);
if (test == NULL) goto err;
if (!BN_lshift(test,BN_value_one(),bits-1)) goto err;
for (;;)
{
for (;;) /* find q */
{
int seed_is_random;
/* step 1 */
if (callback != NULL) callback(0,m++,cb_arg);
if (!seed_len)
{
RAND_pseudo_bytes(seed,SHA_DIGEST_LENGTH);
seed_is_random = 1;
}
else
{
seed_is_random = 0;
seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/
}
memcpy(buf,seed,SHA_DIGEST_LENGTH);
memcpy(buf2,seed,SHA_DIGEST_LENGTH);
/* precompute "SEED + 1" for step 7: */
for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
{
buf[i]++;
if (buf[i] != 0) break;
}
/* step 2 */
EVP_Digest(seed,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
EVP_Digest(buf,SHA_DIGEST_LENGTH,buf2,NULL,HASH, NULL);
for (i=0; i<SHA_DIGEST_LENGTH; i++)
md[i]^=buf2[i];
/* step 3 */
md[0]|=0x80;
md[SHA_DIGEST_LENGTH-1]|=0x01;
if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) goto err;
/* step 4 */
r = BN_is_prime_fasttest(q, DSS_prime_checks, callback, ctx3, cb_arg, seed_is_random);
if (r > 0)
break;
if (r != 0)
goto err;
/* do a callback call */
/* step 5 */
}
if (callback != NULL) callback(2,0,cb_arg);
if (callback != NULL) callback(3,0,cb_arg);
/* step 6 */
counter=0;
/* "offset = 2" */
n=(bits-1)/160;
b=(bits-1)-n*160;
for (;;)
{
if (callback != NULL && counter != 0)
callback(0,counter,cb_arg);
/* step 7 */
if (!BN_zero(W)) goto err;
/* now 'buf' contains "SEED + offset - 1" */
for (k=0; k<=n; k++)
{
/* obtain "SEED + offset + k" by incrementing: */
for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
{
buf[i]++;
if (buf[i] != 0) break;
}
EVP_Digest(buf,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
/* step 8 */
if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0))
goto err;
if (!BN_lshift(r0,r0,160*k)) goto err;
if (!BN_add(W,W,r0)) goto err;
}
/* more of step 8 */
if (!BN_mask_bits(W,bits-1)) goto err;
if (!BN_copy(X,W)) goto err;
if (!BN_add(X,X,test)) goto err;
/* step 9 */
if (!BN_lshift1(r0,q)) goto err;
if (!BN_mod(c,X,r0,ctx)) goto err;
if (!BN_sub(r0,c,BN_value_one())) goto err;
if (!BN_sub(p,X,r0)) goto err;
/* step 10 */
if (BN_cmp(p,test) >= 0)
{
/* step 11 */
r = BN_is_prime_fasttest(p, DSS_prime_checks, callback, ctx3, cb_arg, 1);
if (r > 0)
goto end; /* found it */
if (r != 0)
goto err;
}
/* step 13 */
counter++;
/* "offset = offset + n + 1" */
/* step 14 */
if (counter >= 4096) break;
}
}
end:
if (callback != NULL) callback(2,1,cb_arg);
/* We now need to generate g */
/* Set r0=(p-1)/q */
if (!BN_sub(test,p,BN_value_one())) goto err;
if (!BN_div(r0,NULL,test,q,ctx)) goto err;
if (!BN_set_word(test,h)) goto err;
if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
for (;;)
{
/* g=test^r0%p */
if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
if (!BN_is_one(g)) break;
if (!BN_add(test,test,BN_value_one())) goto err;
h++;
}
if (callback != NULL) callback(3,1,cb_arg);
ok=1;
err:
if (!ok)
{
if (ret != NULL) DSA_free(ret);
}
else
{
ret->p=BN_dup(p);
ret->q=BN_dup(q);
ret->g=BN_dup(g);
if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
{
ok=0;
goto err;
}
if ((m > 1) && (seed_in != NULL)) memcpy(seed_in,seed,20);
if (counter_ret != NULL) *counter_ret=counter;
if (h_ret != NULL) *h_ret=h;
}
if (ctx != NULL) BN_CTX_free(ctx);
if (ctx2 != NULL)
{
BN_CTX_end(ctx2);
BN_CTX_free(ctx2);
}
if (ctx3 != NULL) BN_CTX_free(ctx3);
if (mont != NULL) BN_MONT_CTX_free(mont);
return(ok?ret:NULL);
}
static int dsa_builtin_paramgen(DSA *ret, int bits,
unsigned char *seed_in, int seed_len,
int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
{
int ok=0;
unsigned char seed[SHA_DIGEST_LENGTH];
unsigned char md[SHA_DIGEST_LENGTH];
unsigned char buf[SHA_DIGEST_LENGTH],buf2[SHA_DIGEST_LENGTH];
BIGNUM *r0,*W,*X,*c,*test;
BIGNUM *g=NULL,*q=NULL,*p=NULL;
BN_MONT_CTX *mont=NULL;
int k,n=0,i,b,m=0;
int counter=0;
int r=0;
BN_CTX *ctx=NULL;
unsigned int h=2;
if(FIPS_selftest_failed())
{
FIPSerr(FIPS_F_DSA_BUILTIN_PARAMGEN,
FIPS_R_FIPS_SELFTEST_FAILED);
goto err;
}
if (FIPS_mode() && (bits < OPENSSL_DSA_FIPS_MIN_MODULUS_BITS))
{
DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN, DSA_R_KEY_SIZE_TOO_SMALL);
goto err;
}
if (bits < 512) bits=512;
bits=(bits+63)/64*64;
/* NB: seed_len == 0 is special case: copy generated seed to
* seed_in if it is not NULL.
*/
if (seed_len && (seed_len < 20))
seed_in = NULL; /* seed buffer too small -- ignore */
if (seed_len > 20)
seed_len = 20; /* App. 2.2 of FIPS PUB 186 allows larger SEED,
* but our internal buffers are restricted to 160 bits*/
if ((seed_in != NULL) && (seed_len == 20))
{
memcpy(seed,seed_in,seed_len);
/* set seed_in to NULL to avoid it being copied back */
seed_in = NULL;
}
if ((ctx=BN_CTX_new()) == NULL) goto err;
if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
BN_CTX_start(ctx);
r0 = BN_CTX_get(ctx);
g = BN_CTX_get(ctx);
W = BN_CTX_get(ctx);
q = BN_CTX_get(ctx);
X = BN_CTX_get(ctx);
c = BN_CTX_get(ctx);
p = BN_CTX_get(ctx);
test = BN_CTX_get(ctx);
if (!BN_lshift(test,BN_value_one(),bits-1))
goto err;
for (;;)
{
for (;;) /* find q */
{
int seed_is_random;
/* step 1 */
if(!BN_GENCB_call(cb, 0, m++))
goto err;
if (!seed_len)
{
RAND_pseudo_bytes(seed,SHA_DIGEST_LENGTH);
seed_is_random = 1;
}
else
{
seed_is_random = 0;
seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/
}
memcpy(buf,seed,SHA_DIGEST_LENGTH);
memcpy(buf2,seed,SHA_DIGEST_LENGTH);
/* precompute "SEED + 1" for step 7: */
for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
{
buf[i]++;
if (buf[i] != 0) break;
}
/* step 2 */
EVP_Digest(seed,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
EVP_Digest(buf,SHA_DIGEST_LENGTH,buf2,NULL,HASH, NULL);
for (i=0; i<SHA_DIGEST_LENGTH; i++)
md[i]^=buf2[i];
/* step 3 */
md[0]|=0x80;
md[SHA_DIGEST_LENGTH-1]|=0x01;
if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) goto err;
/* step 4 */
r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
seed_is_random, cb);
if (r > 0)
break;
if (r != 0)
goto err;
/* do a callback call */
/* step 5 */
}
if(!BN_GENCB_call(cb, 2, 0)) goto err;
if(!BN_GENCB_call(cb, 3, 0)) goto err;
/* step 6 */
counter=0;
/* "offset = 2" */
n=(bits-1)/160;
b=(bits-1)-n*160;
for (;;)
{
if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
goto err;
/* step 7 */
BN_zero(W);
/* now 'buf' contains "SEED + offset - 1" */
for (k=0; k<=n; k++)
{
/* obtain "SEED + offset + k" by incrementing: */
for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
{
buf[i]++;
if (buf[i] != 0) break;
}
EVP_Digest(buf,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
/* step 8 */
if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0))
goto err;
if (!BN_lshift(r0,r0,160*k)) goto err;
if (!BN_add(W,W,r0)) goto err;
}
/* more of step 8 */
if (!BN_mask_bits(W,bits-1)) goto err;
if (!BN_copy(X,W)) goto err;
if (!BN_add(X,X,test)) goto err;
/* step 9 */
if (!BN_lshift1(r0,q)) goto err;
if (!BN_mod(c,X,r0,ctx)) goto err;
if (!BN_sub(r0,c,BN_value_one())) goto err;
if (!BN_sub(p,X,r0)) goto err;
/* step 10 */
if (BN_cmp(p,test) >= 0)
{
/* step 11 */
r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
ctx, 1, cb);
if (r > 0)
goto end; /* found it */
if (r != 0)
goto err;
}
/* step 13 */
counter++;
/* "offset = offset + n + 1" */
/* step 14 */
if (counter >= 4096) break;
}
}
end:
if(!BN_GENCB_call(cb, 2, 1))
goto err;
/* We now need to generate g */
/* Set r0=(p-1)/q */
if (!BN_sub(test,p,BN_value_one())) goto err;
if (!BN_div(r0,NULL,test,q,ctx)) goto err;
if (!BN_set_word(test,h)) goto err;
if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
for (;;)
{
/* g=test^r0%p */
if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
if (!BN_is_one(g)) break;
if (!BN_add(test,test,BN_value_one())) goto err;
h++;
}
if(!BN_GENCB_call(cb, 3, 1))
goto err;
ok=1;
err:
if (ok)
{
if(ret->p) BN_free(ret->p);
if(ret->q) BN_free(ret->q);
if(ret->g) BN_free(ret->g);
ret->p=BN_dup(p);
ret->q=BN_dup(q);
ret->g=BN_dup(g);
if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
{
ok=0;
goto err;
}
if (seed_in != NULL) memcpy(seed_in,seed,20);
if (counter_ret != NULL) *counter_ret=counter;
if (h_ret != NULL) *h_ret=h;
}
if(ctx)
{
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
if (mont != NULL) BN_MONT_CTX_free(mont);
return ok;
}
static int probable_prime_dh_safe(BIGNUM *p, int bits, const BIGNUM *padd,
const BIGNUM *rem, BN_CTX *ctx) {
int i, ret = 0;
BIGNUM *t1, *qadd, *q;
bits--;
BN_CTX_start(ctx);
t1 = BN_CTX_get(ctx);
q = BN_CTX_get(ctx);
qadd = BN_CTX_get(ctx);
if (qadd == NULL) {
goto err;
}
if (!BN_rshift1(qadd, padd)) {
goto err;
}
if (!BN_rand(q, bits, BN_RAND_TOP_ONE, BN_RAND_BOTTOM_ODD)) {
goto err;
}
/* we need ((rnd-rem) % add) == 0 */
if (!BN_mod(t1, q, qadd, ctx)) {
goto err;
}
if (!BN_sub(q, q, t1)) {
goto err;
}
if (rem == NULL) {
if (!BN_add_word(q, 1)) {
goto err;
}
} else {
if (!BN_rshift1(t1, rem)) {
goto err;
}
if (!BN_add(q, q, t1)) {
goto err;
}
}
/* we now have a random number 'rand' to test. */
if (!BN_lshift1(p, q)) {
goto err;
}
if (!BN_add_word(p, 1)) {
goto err;
}
loop:
for (i = 1; i < NUMPRIMES; i++) {
/* check that p and q are prime */
/* check that for p and q
* gcd(p-1,primes) == 1 (except for 2) */
BN_ULONG pmod = BN_mod_word(p, (BN_ULONG)primes[i]);
BN_ULONG qmod = BN_mod_word(q, (BN_ULONG)primes[i]);
if (pmod == (BN_ULONG)-1 || qmod == (BN_ULONG)-1) {
goto err;
}
if (pmod == 0 || qmod == 0) {
if (!BN_add(p, p, padd)) {
goto err;
}
if (!BN_add(q, q, qadd)) {
goto err;
}
goto loop;
}
}
ret = 1;
err:
BN_CTX_end(ctx);
return ret;
}